Ventilator



D'ec. 29, 1942. H. HILL 2,306,727

VENTILATOR Filed June 22, 1940 wwfullllujul Patented Dec. 29, 1942 UNITED STATES PATENT OFFICE vEN'rmA'ron Hugh Hill, Anderson, Ind. Application June z2, 1940, serial No. 341,789

(ci. 23o-4s) 9 Claims.

This invention relates to a device which with an associated fan is adapted for use to move air,

especially for exhaust purposes or-for circulating.

In the operation of a fan in free air, the blast of air immediately ahead of the fan is in the form of a hollow cylinder, and the air which passes through the fan is but a small proportion of the total amount of air' moved. The blast of air which passes through the fan draws in air from the sides of such blast and moves that air. When such a fan is used for exhaust purposes, it is normally mounted in an opening not much larger than the fan diameter with the fan close to the plane of the wall through which the opening extends. This arrangement materially reduces the possible efficiency of the fan because it prevents the blast of air from drawing in and exhausting any air except substantially .that which passes through the fan itself.

It is the object of my invention to provide a device which will efciently take advantage of the tendency of a blast of air from the fan to draw in and move air which lies at the sides of the blast. It is my object to secure the exhaust movement of a large volume of air eiciently and quietly with a relatively small fan.

In accomplishing the objects of my invention I mount a. fan in position so that its blast is received by a large end of a frusto-conical nozzle which has a discharge small end smaller than the fan diameter, so that the air blast is compressed and made more uniform over its whole area. This nozzle discharges through a gas passage of gradually increasing cross sectional area and formed as a series of venturis, with a large inlet opening at each of the venturis through which the blast of air from the fan induces air ow.

The accompanying drawing illustrates my invention. In such drawing, Fig. 1 is a vertical section of an exhaust device embodying my invention; and Fig. 2 is an end elevation of the device shown in Fig. 1.

The device shown in the drawing comprises a ring I adapted to be mounted in an outlet opening in a. wall II. Circumferentially spaced frame members I2 are supported on a ring I0 and extend rearwardly therefrom to a smaller ring I3 at their rear ends. A fan I4 and its motor I5 are mounted in position immediately behind the ring I3 so that the fan I4 will discharge through such ring I3. The inner diameter of the ring I3 is slightly larger than the fan diameter. Desirably, a frusto-conical casing I6 is supported by the ring I3 around the fan I4 to form an air inlet passage thereto. A frusto-conical nozzle I'l is carried at its large rear end by the ring I3 and extends forwardly therefrom. Its forward and smaller end provides a discharge opening having a diameter approximately threequarters the fan diameter. The conical walls of the nozzle I1 have an inclined angle of approximately 30. Forwardly of the nozzle II there are a series of nested frusto cones I8. The walls of each has an included angle the same as that of the nozzle I1, and their inner and smaller ends lie on the surface of an imaginary cone having an apical angle of 10. The exhaust end of the nozzle I'I also lies on this surface. Desirably, the walls of the frusto cones I8 have a length equal to approximately three-quarters of the fan diameter, and the cones are spaced in their nested relationship so that each overlaps its preceding one approximately a quarter of its wall-length. At the small end of each frusto cone I8 there is a flange I9 which ares outwardly from the surface of the imaginary 10 cone at an angle of the order of 15.

Each frusto cone I8 is suitably supported at the frame'member I2. In the drawing I have shown the frame members I2 as inwardly open channels and the mounting for the frusto cones I8 as ngers 20 extending between the legs of the channels and suitably secured as by riveting to the webs of the channels.

In this structure, the fan I4 discharges a blast of air through the ring I3 and into the compressing nozzle I'I, in which the cylindrical character of the blast is substantially eliminated so that the air issues from the nozzle I1 at a more uniform rate over its whole cross-sectional area. As the air travels through the passage within the imaginary cone, it reacts at each of the flanged ends of the frusto cones I8 to set up an ejector action which causes a flow of air inwardly through the passages between the nested frusto cones I8 to increase the volume of air passing through the gas passage. This action is repeated at each of the frusto cones I8 so that the volume of air exhausted is much greater than that which issues from the nozzle I1.

The device is of simple construction, it greatly increases the capacity of a small fan, and moves and exhausts a large volume of air in proportion to the size of the fan. It is much more quiet in operation and less expensive to operate than would be a fan which when mounted at the exhaust opening will be sufficient to move an equivalent quantity of air.

My exhaust device is especially adapted for use in exhausting air which carries dust particles or paint, as from a spray booth or sandblast room, for it can be mounted with its rear end connected to the rear wall 2i of such a spray booth so that the air which passes through the fan I4 and past the motor I5 is free from such dust or paint particles. while the dust or paint-laden air is exhausted by being drawn between the frusto cone i8 into the blast of clean air from the fan I4.

I claim as my invention: l

1. An exhaust device, comprising a fan, a frusto-conical nozzle disposed with its large end in position to receive the blast of the fan and having a small end smaller than the diameter of the fan, a series of frusta-conical members of similar apical angle associated with said nozzle. said members being of progressively increasing diameter along the series toward the exhaust end thereof, disposed with their small ends toward such exhaust end, and being axially spaced less than the axial lengths of the members, whereby the small ends of the members lie on the surface of an imaginary cone, and a flange at the small end of each of said members extending toward the exhaust end of the series and flared outwardly away from the surface of said imaginary cone.

2.,An exhaust device, comprising a primary gas-mover, a nozzle through which said gasmover discharges, a series of frusto-conical members of similar apical angle associated with said nozzle, said -members being of progressively increasing diameter along the series toward the exhaust end thereof, disposed with their small ends toward such exhaust end, and being axially spaced less than the axial lengths of the members, whereby the small ends of the members lie on the surface of our imaginary cone, and a ange at the small end of each of said members extending toward the exhaust end of the series and flared outwardly away from the surface of said imaginary cone.

3. An exhaust device, comprising a fan, a frusto-conical nozzle disposed with its large end in position to receive the blast from the fan and having a small end approximately three-fourths the diameter of the fan, a series of frusto-conical members associated with said nozzle, said members each having an apical angle of approximately 30 and a wall length approximately threefourths the diameter of the fan, said members being disposed with their small ends toward the exhaust end of the series 'and axially spaced from each other and being or progressively increasing diameter along the series whereby their small ends lie on the surface of an imaginary cone with an apical angle of approximately 10, and a flange at the small end of each member extending toward the exhaust end of the series and flared outwardly away from the surface of said imaginary cone.

4. An exhaust device, comprising a fan, a frusto-conical nozzle disposed with its large end in position to receive the blast from the fan and having a small end approximately three-fourths the diameter of the fan, a series of frusto-conical members associated with said nozzle, said members each having an apical angle of approximately 30 and a wall length approximately three-fourths the diameter of the fan, said members being disposed with their small ends toward the exhaust end of the series and axially spaced from each other and being of progressively increasing diameter along the series whereby their small ends lie on the surface of an imaginary cone with an apical angle of approximately 10.

5. An exhaust device, comprising a fan. a nozzle positioned to receive the blast4 of the fan and to reduce the diameter of such blast, means ,forming a co-axial series of venturis and defining an unobstructed gas passage therethrough arranged to receive the blast from said nozzle and convey it to a discharge point, said venturis being of increasing cross-sectional area toward the discharge end of said passage, and inlets communicating with said passage at each said venturi and opening into the said passage at a small angle with respect to the axis thereof, through which inlets gas enters and is entrained by the ow of said blast through said series of venturis.

6. An exhaust device, comprising a primary gas-mover, means forming an open gas-passage through which said gas mover discharges and leading to an exhaust point, said passage-forming means including a series of spaced walls inclined at a small angle with respect to and toward said gas passage and forming inlet passages between them, said walls being successively farther from the axis of said passage in the direction of ow therethrough whereby said gaspassage is of increasing cross-sectional area toward said exhaust end and gas is drawn through said inlet passages and entrained by the flow of said blast through the open gas-passage, and flanges on said walls at the inner ends thereof inclined away from the axis of said gas-passage to increase the cross-sectional areas defined by said flanges at a greater rate than that of the open gas-passage.

7. The combination dened in claim 6 in which the primary gas mover is arranged to receive gas from one source and the said inlet passages receive gas from a second separate source.

8. An exhaust device, comprising a fan, a frusto-conical nozzle positioned to receive the blast from said fan, the small end of the nozzle being smaller than the fan diameter and arranged to discharge into an open gas passage leading to an exhaust point, said gas passage being formed of means including a series of spaced walls inclined at a small angle with respect to and toward said gas passage and forming inlet passages between them, said walls being successively farther from the axis of said passage in the direction of flow therethrough whereby said gas-passage is of increasing cross-sectional area toward said exhaust end and gas is drawn through said inlet passages and entrained by the ow of said blast through the open gas-passage,

` and flanges on said walls at the inner ends thereof inclined away from said gas passage.

9. An exhaust device, comprising a fan, a frusto-conical nozzle receiving the blast from said fan and having a discharge small end of approximately three-fourths the fan diameter, a gas-passage into which said nozzle discharges, and formed by a co-axial series of frusto-cones of similar apical angle of the order of 30 and disposed with their small ends in the direction of ow and on the surface of an imaginary cone with an apical angle of the order of 10, said nozzle small end also lying on said surface, and flanges at the small ends of said frusto cones iiaring outwardly from said imaginary cone.

HUGH HILL.

fond column, line 7, for "inclined" read 'inc1uded; page 2 first column,

conform' to the recordo` the casle inl the Patent Office.

CERTIFICATE 6F GORREGYTIONL`--S l j 3 Patent No. 2,506,727. Y December 29, 1914.2. HUGH HILL. f

vTt 'is hereby certified thet error'appeersw in the' prntedspecification of the above numbered patent requiring correction ae follows: :Page 1',- secline- 51|., claim'j, for "beingor" rea'd "being of; andthatthe s'aid' Letters Petent should be read with. this.' correction therein that the same my signed and sealed this 16th' day of February, A, D. 1915. v

- l 4Henry Van Ar.sda1e,.. r

(seal) Acting commissioner 'tf1-Patents; 

